Recently, an execution of payments, authentication, and other functions with wearable devices has become more and more attractive. According to recent surveys, a ring as a payment device has been seen as the most important and popular form factor. In contrast to other wearables, e.g. watches, a ring may include no electronics. Therefore, there may be no power supply available. A passive payment solution may be required. At present, several near field communication (NFC) ring products are available. However, they may not be optimized in design and performance. Several improvements may be possible.
As shown in FIG. 1 (which shows a standard antenna design having a rectangular flex print soldered into a ring form factor), a core of a state of the art NFC-ring form factor may consist of a standard flex-print PCB that may realize a coil antenna. The flex print technology may offer several advantages. It may for example serve as an NFC chip carrier, with a chip being attached to a flex print using standard bonding, flip chip, or the like, may allow a realization of very precise antenna parameters, may provide a technically robust technology, may be cheap in mass production, and may allow to use a non-conductive carrier, e.g. a plastic carrier.
However, up to now, there is no reasonably cheap robust high-performance NFC ring available.